As Rostam grew older, it became clear that he had the potential to be a great warrior. His father Zal promised to find a horse worthy of him - one that would be courageous in the midst of battle. Rostam was given the pick of all the horses that roamed Zabolestan and Kabolestan. He picked a mare who was famous for his speed and spirit. This horse was almost impossible to catch - for three years warriors had attempted to tame it and had failed. Rostam was impressed:
'Its body was a wonder to behold,
Like saffron petals, mottled red and gold;
Brave as a lion, a camel for its height,
An elephant in massive strength and might'
Defying all expectations, Rostan was able to catch and mount the horse. He named it Rakhsh, the Persian word for lightening. Rostam felt it was fated that Rakhsh was his horse. They went on the have many adventures together.